re PR c++/54537 (undiagnosed using-declaration conflicting with used function)

gcc/cp/
        PR c++/54537
        * cp-tree.h: Check OVL_USED with OVERLOAD_CHECK.
        * name-lookup.c (do_nonmember_using_decl): Make sure we have an
	OVERLOAD before calling OVL_USED. Call diagnose_name_conflict
	instead of issuing an error without mentioning the conflicting
	declaration.

libstdc++-v3/
        PR c++/54537
	* include/tr1/cmath: Remove pow(double,double) overload, remove a
	duplicated comment about DR 550. Add a comment to explain the
	issue.
	* testsuite/tr1/8_c_compatibility/cmath/pow_cmath.cc: New.

gcc/testsuite/
        PR c++/54537
        * g++.dg/overload/using3.C: New.
	* g++.dg/overload/using2.C: Adjust.
	* g++.dg/lookup/using9.C: Likewise.

Co-Authored-By: Peter Bergner <bergner@vnet.ibm.com>

From-SVN: r201414

gcc/cp/ChangeLog

+2013-08-01  Fabien Chêne  <fabien@gcc.gnu.org>
+
+	PR c++/54537
+	* cp-tree.h: Check OVL_USED with OVERLOAD_CHECK.
+	* name-lookup.c (do_nonmember_using_decl): Make sure we have an
+	OVERLOAD before calling OVL_USED. Call diagnose_name_conflict
+	instead of issuing an error without mentioning the conflicting
+	declaration.
+
 2013-07-31  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* parser.c (cp_parser_sizeof_pack): Check cp_parser_identifier

gcc/cp/cp-tree.h

@@ -346,7 +346,7 @@ typedef struct ptrmem_cst * ptrmem_cst_t;
 /* If set, this was imported in a using declaration.
    This is not to confuse with being used somewhere, which
    is not important for this node.  */
-#define OVL_USED(NODE)		TREE_USED (NODE)
+#define OVL_USED(NODE)		TREE_USED (OVERLOAD_CHECK (NODE))
 /* If set, this OVERLOAD was created for argument-dependent lookup
    and can be freed afterward.  */
 #define OVL_ARG_DEPENDENT(NODE) TREE_LANG_FLAG_0 (OVERLOAD_CHECK (NODE))

gcc/cp/name-lookup.c

@@ -2316,8 +2316,7 @@ push_overloaded_decl_1 (tree decl, int flags, bool is_friend)
 		  && compparms (TYPE_ARG_TYPES (TREE_TYPE (fn)),
 				TYPE_ARG_TYPES (TREE_TYPE (decl)))
 		  && ! decls_match (fn, decl))
-		error ("%q#D conflicts with previous using declaration %q#D",
-		       decl, fn);
+		diagnose_name_conflict (decl, fn);
 
 	      dup = duplicate_decls (decl, fn, is_friend);
 	      /* If DECL was a redeclaration of FN -- even an invalid
@@ -2549,7 +2548,7 @@ do_nonmember_using_decl (tree scope, tree name, tree oldval, tree oldtype,
 		  if (new_fn == old_fn)
 		    /* The function already exists in the current namespace.  */
 		    break;
-		  else if (OVL_USED (tmp1))
+		  else if (TREE_CODE (tmp1) == OVERLOAD && OVL_USED (tmp1))
 		    continue; /* this is a using decl */
 		  else if (compparms (TYPE_ARG_TYPES (TREE_TYPE (new_fn)),
 				      TYPE_ARG_TYPES (TREE_TYPE (old_fn))))
@@ -2564,7 +2563,7 @@ do_nonmember_using_decl (tree scope, tree name, tree oldval, tree oldtype,
 			break;
 		      else
 			{
-			  error ("%qD is already declared in this scope", name);
+			  diagnose_name_conflict (new_fn, old_fn);
 			  break;
 			}
 		    }

gcc/testsuite/ChangeLog

+2013-08-01  Fabien Chêne  <fabien@gcc.gnu.org>
+	    Peter Bergner  <bergner@vnet.ibm.com>
+
+	PR c++/54537
+	* g++.dg/overload/using3.C: New.
+	* g++.dg/overload/using2.C: Adjust.
+	* g++.dg/lookup/using9.C: Likewise.
+
 2013-08-01  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
 	* gcc.target/arm/pr46972-2.c: New test.

gcc/testsuite/g++.dg/lookup/using9.C

@@ -21,11 +21,11 @@ void h()
   f('h');
   f(1);         // { dg-error "ambiguous" }
   // { dg-message "candidate" "candidate note" { target *-*-* } 22 }
-  void f(int);  // { dg-error "previous using declaration" }
+  void f(int);  // { dg-error "previous declaration" }
 }
 
 void m()
 {
   void f(int);
-  using B::f;   // { dg-error "already declared" }
+  using B::f;   // { dg-error "previous declaration" }
 }

gcc/testsuite/g++.dg/overload/using2.C

@@ -45,7 +45,7 @@ using std::C1;
   extern "C" void exit (int) throw ();
   extern "C" void *malloc (__SIZE_TYPE__) throw () __attribute__((malloc));
 
-  void abort (void) throw ();
+  void abort (void) throw (); // { dg-message "previous" }
   void _exit (int) throw (); // { dg-error "conflicts" "conflicts" }
                              // { dg-message "void _exit" "_exit" { target *-*-* } 49 }
 
@@ -54,14 +54,14 @@ using std::C1;
                            // { dg-message "void C1" "C1" { target *-*-* } 53 }
 
   extern "C" void c2 (void) throw ();
-  void C2 (void) throw ();
+  void C2 (void) throw (); // { dg-message "previous" }
 
   int C3 (int) throw ();
 
 using std::malloc;
-using std::abort; // { dg-error "already declared" }
+using std::abort; // { dg-error "conflicts" }
 using std::c2;
-using std::C2; // { dg-error "already declared" }
+using std::C2; // { dg-error "conflicts" }
 
 using std::c3; using other::c3;
 using std::C3; using other::C3;

gcc/testsuite/g++.dg/overload/using3.C

+// { dg-do compile }
+
+namespace a
+{
+  void f(int);
+}
+
+namespace b
+{
+  void f(int); // { dg-message "previous" }
+  void g()
+  {
+    f (3);
+  }
+  using a::f; // { dg-error "conflicts" }
+}

libstdc++-v3/ChangeLog

+2013-08-01  Fabien Chêne  <fabien@gcc.gnu.org>
+
+	PR c++/54537
+	* include/tr1/cmath: Remove pow(double,double) overload, remove a
+	duplicated comment about DR 550. Add a comment to explain the
+	issue.
+	* testsuite/tr1/8_c_compatibility/cmath/pow_cmath.cc: New.
+
 2013-07-31  Tim Shen  <timshen91@gmail.com>
 
 	Thompson matcher refactored. Fix grouping problem.

libstdc++-v3/include/tr1/cmath

@@ -846,10 +846,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     nexttoward(_Tp __x, long double __y)
     { return __builtin_nexttoward(__x, __y); }
 
-  // DR 550. What should the return type of pow(float,int) be?
-  // NB: C++0x and TR1 != C++03.
-  //   using std::pow;
-
   inline float
   remainder(float __x, float __y)
   { return __builtin_remainderf(__x, __y); }
@@ -985,9 +981,18 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
   // DR 550. What should the return type of pow(float,int) be?
   // NB: C++0x and TR1 != C++03.
-  inline double
-  pow(double __x, double __y)
-  { return std::pow(__x, __y); }
+
+  // The std::tr1::pow(double, double) overload cannot be provided
+  // here, because it would clash with ::pow(double,double) declared
+  // in <math.h>, if <tr1/math.h> is included at the same time (raised
+  // by the fix of PR c++/54537). It is not possible either to use the
+  // using-declaration 'using ::pow;' here, because if the user code
+  // has a 'using std::pow;', it would bring the pow(*,int) averloads
+  // in the tr1 namespace, which is undesirable. Consequently, the
+  // solution is to forward std::tr1::pow(double,double) to
+  // std::pow(double,double) via the templatized version below. See
+  // the discussion about this issue here:
+  // http://gcc.gnu.org/ml/gcc-patches/2012-09/msg01278.html
 
   inline float
   pow(float __x, float __y)

libstdc++-v3/testsuite/tr1/8_c_compatibility/cmath/pow_cmath.cc

+// { dg-do compile }
+
+// Copyright (C) 2013 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include <cmath>
+using std::pow;
+#include <tr1/cmath>
+#include <testsuite_tr1.h>
+
+void 
+test01()
+{
+  using namespace __gnu_test;
+
+  float x = 2080703.375F;
+  check_ret_type<float>(std::pow(x, 2));
+  check_ret_type<double>(std::tr1::pow(x, 2));
+}